Odontalgia, or toothache, is one of the most common types of pain experienced by both adults and children. The pain can be severe, leading to disruption of daily activities, including missed work, sleep loss, problems eating, and mood alterations. One of the primary mechanisms contributing to odontalgia is inflammation of the dental pulp, or pulpitis. Cold hypersensitivity is one of the hallmarks of pulpitis. Importantly, te molecular mechanisms involved in cold detection in teeth are unknown. Understanding the neurobiology of cold nociception by dental pulp afferents is important for both identifying new strategies for dental pain management and providing insight into the neurobiology of cold nociception. Multiple receptors are potentially involved in the detection and transduction of noxious and non-noxious cold, two of which belong to the transient receptor potential family, the TRPM8 and TRPA1 receptors. This proposal seeks to characterize pulpal afferents, in respect to TRPM8 and TRPA1 expression and function, in order to explicate their role in transducing noxious cold in teeth. Studies in Specific Aim 1A will evaluate TRPM8 and TRPA1 expression and function in the population of trigeminal sensory neurons innervating dental pulp using neuroanatomical methods. Specific Aim 1B will utilize pharmacologic and genetic approaches to evaluate TRPM8 and TRPA1 receptor activity in cells projecting to dental pulp using calcium microfluorometry. Specific Aim 2 will evaluate the contribution of TRPM8 and TRPA1 to activation of central trigeminal nociceptive neurons upon noxious cold stimulation of dental pulp. As TRP receptors have emerged as critically important receptors for nociceptive signaling and integration, understanding their expression and function in pulpal fibers is key to understanding one of the most common types of orofacial pain, odontalgia. Further, these studies will contribute to our understanding of the neurobiology of receptors involved in cold nociception.